[PATCH] mmc: dw_mmc: use resource_size_t to store physical address

Andy Shevchenko andy.shevchenko at gmail.com
Thu Nov 12 17:10:13 PST 2015

On Thu, Nov 12, 2015 at 4:14 PM, Arnd Bergmann <arnd at arndb.de> wrote:
> The dw_mmc driver stores the physical address of the MMIO registers
> in a pointer, which requires the use of type casts, and is actually
> broken if anyone ever has this device on a 32-bit SoC in registers
> above 4GB. Gcc warns about this possibility when the driver is built
> with ARM LPAE enabled:

> -       host->phy_regs = (void *)(regs->start);
> +       host->phy_regs = regs->start;

>         /* Set external dma config: burst size, burst width */
> -       cfg.dst_addr = (dma_addr_t)(host->phy_regs + fifo_offset);
> +       cfg.dst_addr = host->phy_regs + fifo_offset;

dst_addr is dma_addr_t?

>         /* Registers's physical base address */
> -       void                    *phy_regs;
> +       resource_size_t         phy_regs;

If dst_addr is dma_addr_t wouldn't be a problem when
resource_size_t is defined as 64-bit address, and dma_addr_t as 32-bit?

Btw, for me casting to dma_addr_t looks sane.

With Best Regards,
Andy Shevchenko

More information about the linux-arm-kernel mailing list